<!DOCTYPE html>
<html>
    <head>
        <style>
            /* div {width: 500px;}
            p {text-indent: 20%;} */
            div#outer {width: 500px; background-color: grey;}
            div#inner {text-indent: 10%; }
            p {width: 200px; background-color: green;}
        </style>
    </head>

    <body>
        <!-- <div>
            <p>this is a paragraph</p>
        </div> -->
        <div id="outer">
            <div id="inner">some text. some text.
                <p>this is a paragraph</p>
            </div>
        </div>>
    </body>
</html>